Yes parents are very welcome to attend matches - the difficulty mainly seems to be figuring out when and where they're happening but parents and their dogs line the pitches for matches to see their sons.
There are 4 short leaves a year where the school closes completely (exeats) and also B weekends where boys can come home on Saturday night, need to be back at 6.15pm on Sunday for absence. Senior boys get more of these I think and of course you can always ask housemasters if there's any flexibility for special arrangements for eg. a family event, a landmark birthday etc.
Pastoral care - I have always found it to be excellent given the fact that it is a very big full boarding school that expects a high level of independence and get up and go from the boys, and that everyone is madly busy at all times eg. the housemaster or dame is not going to be able to respond to my every email or pick up the phone at all times, or tell me down to the minute how much GCSE revision my son has been doing, the HM has 50 other boys to look after and is teaching a 50% timetable as well. However, I do like the way they take a huge school and break it down into smaller groups, 50 boys in a house, 10 boys in a block, 6 boys in a tutor group etc. plus co-curricular points of contact, theatre, music, sport etc who see boys in other settings or contexts to see how he is. So a boy has multiple points of pastoral contact daily and the Stephenson Centre is absolutely invaluable as a resource. (I have a friend who is on an 8+ month waiting list for multiple private therapists for her daughter, whereas boys can be seen pretty much immediately through school with or without a referral).
I know some parents are driven crazy by the fact that it is full boarding and they are giving up control or they don't have as much daily communication as they would have if he was at a day school and they see him every evening. But if you choose a full boarding school that's what you're going to get and I don't understand parents who choose Eton and then get angry about their son not calling them every night, or trying to micromanage their academics from afar. Eton is not for everyone, other schools are available and full boarding will definitely not suit every family. And most parents seem to be at school every 5 minutes anyway with plays, concerts, sports, dropping off or picking up for weekends, etc.
@Nowand4ever What is a negative for some is a positive for others and that's why it's good to have choices. It's the right school for my son at the moment and for him, it's streets ahead of any alternative by a mile. That's not to say I wouldn't pull him out if that changes in future. I went to a top Ivy League university that wasn't all it was cracked up to be and I wouldn't lose any sleep if my kids didn't go to the same one for undergrad, I feel the same way about Eton or any school for that matter. The only poster on here I know who fits your description is peteneras and I don't agree with her on many things...